A Triangular Turn of Events
by Get Keen
Summary: When Dipper is visited by Bill in a dream and accidentally makes a deal with him, his life goes from weird to utterly impossible. Forget the ideal 'upside-down triangle' figure that every guy craves...he's the real deal, now! Hilarity ensues in this new take on demon!dipper, as he and Mabel try to find out just what Bill has to gain from all this chaos. [I don't own Gravity Falls!]
1. Chapter 1

**Chapter 1**

"What the – just _what_ are you doing, Mabel?!"

The flat-capped, twelve-year-old boy was clearly perturbed by his sister's actions, despite the fact that he should have been used to her antics by now. Having come into the world only five minutes after her should lead to becoming comfortable with her many quirks quite quickly; however, 'comfortable' was not a word Dipper Pines would use to describe how he was feeling at this moment.

Mabel Pines, twin sister to the former, oddly nicknamed boy, was approaching her terrified sibling armed with an entire bag of sparkly makeup. Just behind the crazed preteen, were her trusty sidekicks who had been promised a chance to give the unfortunate boy a _total makeover._

"Mabel! C'mon sis! Why are you doing this?!" Dipper cried out melodramatically, as his eyes darted around the twins' shared, attic bedroom in search of a path of escape.

Mabel didn't reply, a manic grin curling her mouth and exposing her braces as she and her minions only advanced menacingly.

"I'll do whatever you want! Just don't make me all glittery again!" The boy shut his eyes tightly and held his hands out in surrender. Mabel halted abruptly and her eyes lit up mischievously.

"Anything, bro bro?" the makeup bag in her hands fell to the floor as she straightened up, putting a hand to her chin as if she was seriously considering his offer.

After only a short moment of pondering, she swiftly crossed the remaining distance between her brother and stuck out a small, four-fingered hand. Dipper looked up hesitantly, and breathed a sigh of relief to see that she had abandoned her weapons.

"I'll figure out what you can do for me later, Dipping Sauce. But you got yourself a deal," she winked at her brother good-naturedly as he wiped imaginary, nervous sweat off of his brow and gave her a small smile.

He shook her hand…

and everything changed.

Mabel's smile grew unnaturally large and twisted, her pupils lengthened alarmingly, and her body began to expand rapidly, whilst her head, as if to contrast this sudden growth, narrowed to a point. By the time the unnerving transformation was complete, Dipper was staring aghast at the unmistakable form of the triangular psychopath, and dream demon extraordinaire, Bill Cipher.

And he was in absolute hysterics.

The two-dimensional demon was folded at the middle, literally doubled over with laughter, as he cackled maniacally, **"It's not just funny anymore Pine Tree; it's actually getting sad to see just how dumb you actually are."**

Dipper scowled, the shock of having seen his sister morph into the creature he hated most in the world wearing off as anger overshadowed his fear.

"What do you _want,_ Bill?" He snarled at the triangle.

Bill straightened his bowtie and pulled a sleek, black cane out of nowhere, leaning on it as he responded, **"** ** _Excellent_** **question, Pine Tree! No really, it is; seeing as how you said you'd do** ** _whatever_** **I wanted, and then** ** _shook on it._** **"**

The yellow triangle summoned the signature blue flames around his right hand, the hand that had been _Mabel's_ only a moment ago, and Dipper visibly paled. Seeing this, Bill chuckled again, but this time it was more subdued, and much darker.

 **"** **Oh the** ** _fun_** **we're going to have together, Pine Tree. I could make you my slave, erase your memory, make you destroy Gravity Falls for me…oooh, now** ** _that's_** **a good one…"**

The floating dream demon shuddered with pleasure as he rambled on about the several terrible things he could make Dipper do, while the poor boy could only quiver in his sneakers. There was no way out of this one. _That_ little fact, he knew for certain.

 **"** **But,"** the demon had finally finished his twisted monologue, **"I must confess Pine Tree; I've had something in mind for you long before this lovely encounter."**

His eye narrowed gleefully in what was clearly a smirk. Dipper gulped, he definitely wasn't liking this. The evil dorito continued, **"I'll be taking a little** ** _vacation_** **and I need someone to replace me temporarily…"**

He didn't need to finish his proposal for Dipper to understand what it was he was asking of him. The preteen's jaw hit the floor and he finally found his voice, "So, let me get this straight – _you're_ asking _me_ to do your job as a _dream demon?!_ "

Bill cackled, **"** ** _Temporarily,_** **kid. And you wouldn't be a** ** _demon_** **per se, you'd just look like me, respond to summonings, and have a few of my minor powers. You'd still be totally physical and** ** _essentially_** **human. I'll still know when you're messing up, and will step in to take care of the actual deal making after I'm – well,** ** _you're_** **– summoned."** His eye narrowed so much as he laughed his distorted laugh that it was almost shut completely.

Dipper couldn't hide the fact that he was quite relieved at the yellow triangle's request. He wasn't going to enslave him, make him go insane or make him do anything illegal; it seemed almost too good to be true. Surely he, the other half of the Mystery Twins, could deal with a few summonings.

Clearly able to detect this relief, Bill sobered up immediately and grew almost double his size in order to intimidate the feeling out of the boy.

 **"** **Don't get me wrong, Pine Tree,"** his voice was lowering in pitch, **"You won't see it now, but there most definitely** ** _is_** **something in it for me."**

Dipper clenched his teeth and merely nodded, wide-eyed. Almost immediately, the two-dimensional pyramid shrunk down to his normal size and threw a pitch-black, noodle-like arm around his shoulders, **"That's my boy,"** he winked; or rather, blinked.

Dipper shuddered at the unwanted familiarity from the demon, only to realise that he, as well as what was left of the attic they'd occupied, had totally vanished. Dipper was left in a blinding whiteness that confirmed his suspicions. The whole thing with Mabel had been a dream, which was where a Dreamscape-dweller like Bill would be in his element.

Dipper face-palmed as he felt himself beginning to wake up. Stupid Dipping Sauce. Or, to be more accurate in light of his soon-to-be new situation, stupid Pine Tree.

Dipper

I woke up in my normal bed, in my normal attic room, in the nor – well, the Mystery Shack. I, however, was the only abnormal thing in the entire equation. I felt it the moment I opened my eye. Emphasis on the singular. The sudden lack of a whole other perspective woke me up as effectively as a cold bucket of water to the face would have. That, and the fact that Bill had suddenly decided to make his presence felt in the form of telepathic communication. (When did _that_ happen?)

 ** _I forgot one thing Pine Tree,_** I rolled my eye, of course he did.

 ** _No need to be sassy now,_** he let out a snort of laughter, **_I just wanted to tell you that you can't tell anyone that you're you and not me. Capiche?_**

I groaned out loud, and cringed at how much like Bill the timbre of my voice had become. I thought back a silent yes, feeling like an idiot for doing so, and tried to climb out of my bed. It was then that I realised I wasn't in my bed to begin with. Instead, my now triangular figure was floating a few inches _above_ it.

And, what was even worse than that realisation, was this next one. Sitting up in her own bed, gaping at me with an odd combination of surprise and horror on her face, was my twin sister.

 **"** **Oh! Oh, Ma – uh – Star! What a pleasant surprise!"** I cringed inwardly at my goof up, but I couldn't tell her who I really was. If I did, then who _knows_ what that crazed dorito would do to her? No way was I letting Mabel get mixed up in this mess I'd gotten myself into. My new, 'Bill' voice was also really unsettling me. It was disturbing to hear my words come out of Cipher's – whatever he had for a mouth – almost like it was _me_ who had taken over _his_ body. Which, I guess, had sort of happened.

"You're – B – B," Mabel stuttered a horrified greeting. This was honestly the first time I'd ever seen my sister at a loss for words. It was actually pretty funny. I started to chuckle, but quickly cut myself off.

 _What is_ with _you, me?! This is no time to be laughing! Unless those 'minor powers' came with some limited edition, 'Bill'-brand, psychopathic side effects. Oh yeah, that would be just_ fantastic.

I felt a scowl spread across my features, and I clearly must have looked pretty dangerous, because Mabel let out a squeak and scrambled off of her bed. Her pillow fell to the floor, raising a rather impressive dust cloud from the wooden floor that clearly hadn't been cleaned since the Dark Ages. The dust, twinkling in the light from the morning sun, engulfed me mercilessly and I felt a familiar reflex building up as I was forced to scrunch up the area my nose would have been. I must have been a sight to see, the world's most dangerous entity with his eye half closed and polygonal form hunched over in order to gear up for something as mundane as a sneeze.

Unfortunately, I only realised what this meant for both me and Mabel when it was too late. I wouldn't have been surprised to find out that my sneeze sounded like garbled, backwards speech but what actually came out really _did_ shock me to my core.

It sounded…totally normal. A delicate squeak was released from my new frame as I rubbed at where my nose should have been, trying to relieve that ticklish feeling that lingered after a good sneeze. When I registered the sound I had made, I froze mid-rub. I looked back to where Mabel had pressed herself against the wall, only to see that she was standing and that all traces of fear had disappeared from her face.

"You sneeze," she began in awe, "like a kitten."

She knew. Mabel knew that I was me. But what did I think, that I could have actually hidden it from her?

She started approaching me, and I tried to make myself look as unlike the real me as possible. I puffed out my chest and, on a whim, imagined Bill's black cane in my hands. I just managed to hide my surprise when it actually popped up in that exact position and leaned on it, mildly relieved when I saw Mabel start at its sudden appearance. In conjuring it up though, a thought suddenly flitted into my mind. Bill had said that I couldn't _tell_ Mabel I was me. He hadn't said anything about her _figuring it out on her own,_ did he?

Huh, maybe this new, distinctly 'Bill' way of thinking was useful for something after all. _Like finding exploitable loopholes in deals,_ I thought as a smirk made my eye narrow slightly.

Mabel continued to approach me slowly, in spite of the cane's sudden appearance.

When she was still a safe distance away from me, she stopped and simply stared. After a few moments, I cleared my throat awkwardly. Still nothing. She was staring hard at me, as if waiting for something to happen.

Jeez, I forgot how intense my sister could be sometimes. I reached up with my left hand to rub at my forehead, where my birthmark would have been, like I do when I'm feeling particularly uncomfortable. Needless to say, I rubbed my head quite often.

The moment my tar black hand reached my triangular point, Mabel let out a screech that sounded worryingly like some kind of war cry, before lunging at me. She gave me such a fright, that I actually dropped the cane, which simply remained levitating in the position it had been in when I had let it go.

Bill had said I'd still be totally physical, seeing as I wasn't actually a demon. Well, the way Mabel crashed into me, and tackled me to the floor of the attic certainly proved _that_ fact to be true. I felt _all_ of it.

 **"** **What the HECK, Mabel?!"** I yelled at her. I was _angry._ Angrier than I'd felt in my life; and for absolutely no valid reason. I felt my form enlarge, and had seen it happen on Bill enough times to know that my eye, and body, was turning a vivid shade of crimson.

My sister, the weirdo that she is, didn't even flinch. She simply crossed her arms over her chest and lifted an eyebrow at my overreaction. That took all the bluster out of me. I shrank to my original size and took a deep breath, holding it until I was sure I was a placid, unintimidating yellow again.

"I think I should be asking _you_ that, bro bro." She had a point there. I looked down guiltily, but couldn't but help feel joy swelling in my chest at the fact that we'd found a way around Bill's deal. I didn't need to do this alone after all.

I scowled at Mabel as she snorted with unattractive laughter. Honestly, I pour my heart out to her while recounting all my plights from last night and she _laughs_ at me.

"I'm sorry, Dipper," she wiped a tear from her eye, "But out of all the weird things to happen to us at Gravity Falls, I never thought that I'd end up having a tortilla chip for a twin brother."

I huffed and looked down at the floor angrily. Mabel and I were sitting cross-legged on our bedroom floor – or at least she was. It was surprisingly easy to get used to my new, two-dimensional, mildly demonic state; for both me _and_ Mabel; and I had decided to stop trying to get my weird limbs to touch the floor.

My ever-optimistic twin suddenly clapped her hands together decisively and looked me in the eye with an expression more solemn than I'd ever seen her put on in our lives. Jeez, talk about mood swings.

"So, Dipperito," I cringed at the nickname, "Just what kind of mind-blowing powers did you inherit from Bill?"

 **"** **Can you** ** _please_** **not say 'inherit' and stuff like that?"** I face palmed my response, **"He was already being way too weird with the fatherly speak last night. I don't need** ** _you_** **doing it too."**

Mabel gasped and her pupils dilated as she cooked up a scenario in her over active imagination.

"What if you _are_ his son?" she began, "And, like – that's why he gave you his powers…so that you'd remember your life with him before?"

I cringed again at her line of thought, the whole situation was _way_ too close for comfort with my current appearance to be funny.

She continued, undeterred though, "You must have been in a lot of danger for him to pass you off as my brother for all these years. But now, the love of a father for his son will finally win against all the odds stacked against them!"

She finished with a wild fist bump, and I could practically see the American flag fading into view behind her. She looked at me expectantly, but I only grimaced at her as best as I could with my only facial feature being one, oversized eye.

"Too soon?" she cocked her head at me.

"Too soon." I confirmed with a blink.

"Right. Sorry, bro bro!" she punched me where my shoulder would have been, and I rolled my eye.

 **"** **Whatever, Mabel. It's fine,"** I said, but I stopped with the scathing look and let my arms fall to my sides from where I'd had them crossed angrily over my bowtie.

She took this all in her stride however, as she does, and continued to prattle on about discovering my powers. I didn't really pay attention to her though, 'cause a weird feeling had suddenly materialised inside of me. It was like a weird, central tugging; and I didn't know what to make of it.

Just as I was about to say something about it, it suddenly intensified and I felt like my whole body was being pulled out of shape. I felt like laughing, screaming and crying all at the same time, so odd was the sensation. I was trying to figure out just whether or not it was actually painful, when the feeling disappeared all of a sudden. It had dissipated even more abruptly than it had begun.

I opened my eye, which I hadn't realised I'd closed, only to find myself not in the attic of the Mystery Shack anymore.

Instead of the dusty, but admittedly homely wooden room with my weirdo sister in front of me, I was surrounded by cold, grey brick. I let my gaze wander over my new surroundings only to find that they didn't get much more promising, at all. Every opening in the walls was barred with thick cylinders and the only door was made of a heavy, metal amalgamate with a single opening near the floor, that was also covered by bars.

The floor was cracked stone and stained with I-don't-even-want-to-guess what, and had clearly been housing insect colonies for decades. In fact, the only thing that looked even remotely new was circle of chalk with weird, but familiar symbols contained within and…

Oh.

A crudely drawn, but unmistakable Bill Cipher was in the centre.

I had just arrived at my first summoning. Whoop-dee-doo.


	2. Chapter 2

**Chapter 2**

I must look a sight. A dazed, acting dream demon who is clearly out of his element, floating inactively in front of crowd of extremely large, extremely intimidating men. The inmates, for that was what they obviously were, didn't seem to notice my presence, however. They were muttering amongst themselves, and I could pick out a few comments of: "Did it work?" and "I knew this was a bust!" here and there.

Weird. Apparently they couldn't see me, which wasn't a promising sign at all, seeing as I was supposed to be _entirely physical._ But, before I could have a meltdown about this little, worrying fact about my humanity, an unwanted presence returned to my psyche.

 ** _I told you I'd be back after you're summoned Pine Tree!_** I groaned out loud at Bill's voice ringing out annoyingly in my head; _Is this gonna be a regular thing Bill?_

 ** _You bet, kid!_** This time I actually face palmed, yelping as an unwanted blue flame made its presence felt with the slap as well. I scowled as I heard Bill's obnoxious laughter echo through my mind, _Okay! So why are you here, Bill?_ I spat out telepathically, folding my arms over my bowtie again.

 ** _I said I'd handle the actual deal-making didn't I?_** He _did_ say that, I guess.

 ** _But…_** Oh, here we go, ** _I decided that I'd just give you a little help with it instead._**

 _WHAT?! That wasn't part of the deal Bill!_ I replied angrily.

 ** _Technically, it can be part of the deal if I want it too. You_** **did _say you'd do_ anything _I wanted,_** I could practically feel him smirking in my head. It was not a pleasant experience.

 _Fine! Fine. Just – stop bringing that up okay?_ I felt my frown deepen as I let out a resigned sigh, _what do I do?_

 ** _That's the spirit, kid! Lesson one in handling summonings: make an entrance!_**

Now how the heck was I supposed to do that? Oddly enough, the answer came to me sooner than I expected it to, if I expected it to come to me at all. It was almost as if the knowledge was there already, and I should have known what to do all along. In fact, I felt stupid for not remembering in the first place, and _that_ fact mildly disturbed me. I brushed it off as another of Bill's disturbing personality side effects though, not wanting to contemplate any other possibility.

Also, while all these emotions were flowing through my triangular frame, Bill was strangely quiet. I didn't miss him, though. My mind was on other things:

I do have to admit; my entrance idea was pretty awesome. Or Bill's was. Whatever. If it was Bill's idea, the demon-guy actually has a complicated, but totally cool, imagination. He's pretty smart too… **liKE I aM**. I mean, I know I'm intelligent, c'mon. I found that first journal **_siNgLe-hANdEdlY_** _._ Sure, Mabel was there, but it was me – **ME** – who was responsible for all our mind-blowing adventures this summer. If **I hAdN't uSEd MY bRilLiANt sKilLS** of deduction on even **oNe o** f the occasions I had, we wouldn't **Be wHeRe wE** were now…

And I wouldn't finally have **a fORm** capable of expressing my smarts – and all around general **AWESOMENESS –** to the world. **Yeah!** I mean **, it's aBoUT tImE pEOple** regret **ALL tHe tiMes** they **oVErLoOkED me jUSt beCaUsE of** my age **, or sOCiAl i** neptness _._

 ** _I'lL sHOw ThEm JuST wHat ThEY mIsSed OuT oN._**

Roger was fed up. He was one of the few inmates in this particular cell at the Rorschach Rehabilitation Centre who had not been keen on the idea to turn to the unknown for help. Eventually though, seeing as the men who were desperate enough to do so far outnumbered the few who weren't ready to compromise what was left of their sanity, he'd had to relent and had sat in a corner of the large cell, hugging his knees to his chest while the others set about scratching into the floor with their chalk.

He had to admit, though. He was very relieved when nothing had happened after the ritual was over and done with. He was never a religious man per se, but he didn't want to mess with what could possibly be out there. And in any case, he'd rather turn to the Heavens for help, than what seemed to be the opposite. Still, he felt sorry for his fellow inmates. Yes, they wanted to break out of prison, but they weren't necessarily bad guys. Petty criminals, the lot of them were. No murderers, rapists, arsonists, or anything of that sort; heck, Roger himself was in for large scale tax evasion.

The orange-clad man looked up from where he'd been focussing on his hands, which were still wrapped around his knees, to gauge the others' reactions to their failure. Sure enough, they were squabbling like kindergarteners on a playground, pointing fingers and blaming everyone else but themselves for the ritual-gone-wrong. After a while of studying the rowdy group for a few moments though, Roger felt the need to rub his eyes. His vision had gone really weird for a second. He could have sworn he saw the room begin to lose what little colour it had left in its already monotonous walls. When he removed his hands from his face however, he saw that he had indeed been correct.

The multi-coloured chalk marks on the walls left by the inmates who had practiced their drawing skills before creating the summoning thing, had drained to various shades of grey. Roger gulped. He was hoping against hope that what he thought was happening was simply a figment of his imagination.

He was wrong.

A creepy, nasal cackle suddenly filled the room, shutting the shouting inmates up immediately. Collectively, the cell's occupants looked up in the air above the chalk, where the silhouette of a triangle had appeared out of nowhere through which could be seen galaxies and planetary bodies in motion. It was as if they were looking into another dimension through a polygonal doorway and the inmates stared, slack-jawed in their rapt attention at the paranormal rift. The cackling grew louder and a few of the men shuddered at the sound, only for all of them to jump backwards a second later when a large eye blinked into existence on the triangular gap. It had a single, slit pupil that stared eerily back at them as the cackle built into roaring laughter so loud, that all human ears were reflexively covered.

Roger had gone white as a sheet and, unbelievably, was walking towards the crowd while the others were shrinking away from what was clearly their mistake to have summoned in the first place. Suddenly, the laughter cut off as unexpectedly as it had begun, and the cell was left in silence as the triangular silhouette peeled itself away from its place in the air, and seemed to become a solid, two-dimensional pyramid. A top hat was now floating above its head and four limbs had sprouted from its sides, two of which it used now to pull at a black bowtie that had appeared just underneath its eye. The one that was now staring at them with what seemed to be a sneer. If eyeballs could sneer.

 **"Alright boys, I have a proposition for ya."**


End file.
